“…The expansion factor f} was taken to be 1.0, as found in the literature [1,2,21], although other studies consider a greater expansion of the oxide [22,23]. For the normal stiffness, a wide range of values are found in the literature: in [2], the bulk modulus of the oxide was taken to be of the same order of magnitude as the bulk modulus of water (around 2 GPa); in [23,24] the elastic modulus was estimated from a combination of analytical models and experiments in which the radial displacement in concrete was measured by image correlation techniques; the values obtained in these two studies are, however, very different: an elastic modulus of 0.14 GPa is reported in [23] for an assumed Poisson's ratio of the rust of 0.2, while the values of the elastic modulus reported in [24] range between 2 and 20 GPa, and no reference to Poisson's ratio was made by the authors.…”